Fly ash removal system



May 21, 1946. E. C. WEBB 2,400,797

` FLY ASH REMOVAL s YsTEM 'Filed July 28, 1943 3 Sheets-Sheet 1 FITUR/ys Y lMay 21, 1946. E. c. 'WEBB FLY SH REMOVAL SYSTEM 3 Sheetsf-Sheec 2 Filed July 28, 1945 /NL/ENTUR 5.6 wf' [May 21, 1945 AE. fc. WEBB FLY ASH-REMOVAL SYSTEM Filed July 28 1945 3 .Sheets-Sham;

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HTTURNE Y' Patented May 21, 1946 UNITED STATES rPATENT OFFICE L f 2,400,797 :L

FLY AsHfvnEMovAL SYSTEM K l Ernest dwebb. cleveland; ohio Application July 28'. 1943; Serial'No. 496,437

toiai'ms. (o1. 11o- 165) The main object of this invention is to :collect the fly ash from behind the bridge wall of a boiler and return it to the combustion chamber thereof in order that all ofthe combustibles therein may be burned and the heat extracted therefrom;

The second object is toconstruct'a system of the class described which'will be relatively inexpensive to construct and which is at the same time highly efficient. Y

These and other objects are accomplished in the manner set forth in the following speciii'ca`` tion, as illustrated in the accompanying drawings, in which: Y

Fig. 1 is a horizontal section taken alo-ng the line I-I in Fig. 2.

Fig. 2 is a vertical section taken along the line 2-2 in Fig. l.

Fig. 3 is a vertical section taken along the line 3-3 in Fig. 2.

Fig. 4 is a fragmentary front elevation of a boiler front showing a representative installation and cutting through the pneumatic coal feeder along the line 4-4 in Fig. 2.

Similar numerals refer to similar [parts throughout the several views.

Referring in detail to the drawings there is shown a boiler front I having the inspection openings II, ash pit openings I2 and the opening I3 through which is inserted the nozzle I4 of the pneumatic conveyor pipe I5, provided with elbows I6. The tip I1 of the nozzle I4 is preferably made adjustable to assist in controlling the spreading action of the fuel. The usual grates I8 are also indicated.

At the back of the grates I3 is disposed the bridge wall I9 whose rear side'20 slopes downwardly to the ash collection pit 2l whose sides 22 are preferably vertical. The side 23 slopes upwardly from the pit2I to the rear wall 24 of the setting. Communication is gained to the pit 2l through the tunnel 25 which ofpens outwardly through the side wall 26. Across the pit 2| is placed a perforated grating 21 which `extends preferably along the entirerlength of the tunnel 25 to the door 28 which forms a closure for the tunnel 25. The portion of the grating 2T which occupies the tunnel 25 is not perforated.

Below the grating 21 is placed a nozzle 29 of an ash ejector which operates onthe Venturi principle. The Vent'uri tube 30 is connected to the discharge pipe 3| which passes through the elbow 32 at the lower front corner of the furnace, and then upwardly through the elbow 33 and thence discharges through the pipe 34 to the combustion space of the furnace. The location of the pipe 34 will depend largely upon the requirements of a particular installation, and is herein shown` only by way of illustration.

l'I'he nozzle 29 is connected by the pipe 35 to the manifold air box 3B to the upper end of which is connected the pipes 31 which in this case occupy Itis desirable to provide a refractory Yshield E 4I over the pipes 31 and to slope the sides 42 to prevent the accumulation of fly ash thereon. The end-walls 43yand 44 also Vslope toward the center `of the space behind 'the bridge wall I9 so that fly ash settling behind the bridge wall i9 will settle on the surfaces 20, 23, 42, 43 or 44. The slope of the surfaces is such as to discourage thick accumulations of fly ash and to encourage it being deposited on the grate 21 within the pit 2|.

It is obvious that the air-cooled shield reduces the temperature of the ash or combination of ash and combustible material entering the conveyor. Also that this shield reduces the temperature of the perforated grating below the temperature it would obtain if it were exposed directly to the furnace temperature unprotected by this air cooled shield.

It will -be noted that the elbows 32 and 33 are provided with covers 45 which are preferably removable to make it possible to take care of any congestion of ash within the pipe itself, although `tion a furnace including primary and secondary combustion chambersya ily ash collecting pit discssY posed below said secondary combustionchamber and means for shielding said pit from the radiant heat of said secondary combustion chamber for the purpose of preventing the fusing of ily ash deposited within said pit. 2,"A y ash removal system having in com- 3. A ily ash removal system having in combina-I tion a furnace including primary and secondary combustion chambers, the former having a grate` structure upon which fuel may be burned and the latter a, combustion space in which gases re1 leased in said primary chamber, together withV solids carried by said gases are burned in suspension,`an ash collecting pit under said secondary chamber, means for shielding thefly ash g produced in the secondary chamber from `theradiant heat produced therein after .said fly ash has settled, means for holding the temperature of said iily ash below the fusing point While in said pit and means for removing the ash from said pit in an unfused condition. t

4. A ily ash removal system having'in combination a furnace including primary and secondary combustion chambers separated by Va bridge Wall, the primary chamber in front of said .Wall having a grate structure upon which solids may be burned and above which powdered fuel may be burned in suspension, the secondary chamber behindsaid bridge wall being employed to'burn gases released by-said primary chamber and which have passed over said bridge Wall without being consumed, together with particles of solid fuel carried by said partially consumed gases, the bottom of said secondary chamber having sloping sides terminating in an ash collecting tunnel, a shield over said tunnel protecting the y ash therein against direct radiant heat generated in said secondary chamber, means for dissipating heat from said tunnel for the purpose of holding the fly ash therein below the fusing point, and pneumatic means for conveying said cooled ily ash back to the primary combustion chamber.

Y 5. A furnace having a primary combustion chamber a secondary combustion chamber separated from the primary chamber by means of a bridge wall, including a grating at the bottom of said secondary chamber, said secondary chamber having inclined refractory walls converging downwardly toward said grating, a plurality of horizontal cooling pipes disposed over said grating, an ash ejector having its intake below said grating and a fan for forcing air through said cooling pipes and through the ash ejector whereby the temperature. of the ash .on the grating and beneath said grating may be held below an ash fusing temperature.

6. In a furnace having primary and secondary combustion chambers,v the combination of a grating disposed at the bottom of the secondary combustion chamber, a shield of air cooled pipes disposed over said grating, a pneumatic ash ejector disposed under said grating taking air from said cooling pipes and a fan for supplying air to said cooling pipes. l l

ERNEST 1C. WEBB. 

